Manufacture of catalysts



Patented Apr. 3, 1928.

UNITED STATES PATENT OFFICE.

EABALD NIELSEN, OF MUSWELL HILL, LONDON, ENGLAND, ASSIGNOR, OF ONE-HALF TO BRYAN LAING, OF HATFIELD, ENGLAND.

MANUFACTURE OF CATALYSTS.

No Drawing. Original application filed November 27, 1922, Serial No. 608,686, and in- Great Britain December 3, 1921. Divided and this'application filed March -7, 1925. Serial No. 18,916.

This invention is .a division of my pending application, Serial No. 603,696, filed November 27 1922, and relates to the manufacture and utilization of formic acid more especially for use in connection w1th the production or conversion of liqu d hydrocarbons, the chief object of the invention being to crack or transform liquid hydrocarbons or to obtain' an increased yield of the more readily liquefiable constituents or condensible hydrocarbons especially during- -the distillation of carbonaceous materials,

such as coal, lignite, eat, shale, wood and the like. A further 0 ject of the invention is to cheapen and simplify the manufacture or production of formic acid.

As is well understood the amount of liquid or condensible hydrocarbons obtained by destructive or other forms of distillation depends primarily upon the amount of volatile matter contained in the material to be I sible or liquefiable hydrocarbons yielded up during the process of distillation it has been 7 proposed to add to the carbonaceous material before or during the process of distillation certain other materials with the object of exercising a so-called catalytic action there- .on, oxidation or hydrogenation being thereby caused to take place in such a way that the relative proportions of the carbon and hydrogen atoms present in the hydrocarbons have been altered so as to produce newcombinations which give rise to, an increased yield of the more readily liquefiable con- Stituents of the hydrocarbons. One of the substances which it has been proposed .to use for this purpose has been the salts of-formic acid, preferably sodium formate, this substance -be1ng-;;mixed in vari-- ous proportions with the g'carbonaceous materia which is to be diatilledand, by its use,

of so-called air gas, composed principally sub-oxide produced in the foregoing manner a higher proportionate yield of liquid hydrocarbon has been stated to result.

Up to the present time, however, these attempts have been more or less of an experimental character and have not been developed on a commercial scale on account of the fact that the cost of an active catalizer which would roduce oxidization or hydrogenation, or o the sodium formate, was out of all proportion to the vahie of the increased yield of 1 liquefiable hydrocarbons obtained y its use.

According to one feature of the present invention formic acid is produced directly from methane or a gas containing methane, in the presence of-a metallic catalyzer, preferably a metallic oxide catalyzer, or from carbon monoxide in the presence of water vapour and a metallic catalyzer.

A gas also suitable for the catalytic production of formic acid consists for instance of carbon monoxide and nitrogen, or ordinary coal gas, containing methane, or natural gas maybe used. Q

In the case of methane or agas' containing methane the gas is passed over a suitable metallic catalyzer or metallic oxide catalyzer and the'following reaction takes place.

1 In. the presence of the catalyzer, the CO combines with the H 0 to produce formic acid (CH,,O or H.C0.0H).

The metallic catalyzer which I have found most suitable may be manufactured as follows z-Anactivated copper sub-oxide is produced' by precipitatingcopper from a solution of copper sulphate by means of metallic zinc the copper sulphate being greatly in excess so as to insure that no metallic zinc is present. The precipitated copper suboxide is thereafter washed and boiled so as to remove as far as possible all traces of .zinc and afterwards dried and roasted in the air. Although I have found an activated copper to be satisfactory, other copper oxides precipitated from-co per salts (whether organic or inorganic and yany suitable method in cluding Sabatiers method) or ordinary granulated or powdered copper may also be employed, provided the precipitate is activated over and over again... Precipitated copper cut. invention free by being moistened in a zinc sulphate solution.

In manufacturing free formic acid from methane I have found that satisfactory results can be obtained by proceeding as follows Pure methane, made for example, by the dry distillation of sodium acetate and sodium lime in excess, is carefully cleansed of impurities and conducted over or through. the fine spongy granules of an activated copper sub-oxide produced in the foregoing manner. The methane appears to be split up and oxidized in the following manner CHOOH (CHaQx) the resulting products being therefore as follows-- 7 00, 211,0 H, CHOOH- In the foregoing reaction the methane takes its oxygen from the copper sub-oxlde,

as no free oxygen is required. The reaction 1s an endothermic one and requ res a temperature ranging from 250 to 800 centigrade.-

Chemical analysis of the activated copper sub-oxide producedin the foregoing manner shows that it appears to approach very closely the formula Gu O before acting on the methane or carbon monoxide. After a comparatively short time however, the copper sub-oxide becomes inactive and appears to have lost a certain amount of its oxygen, At

the same time it becomes lighter in colour and analysis gives the formula Cu O or Cu Gu O. In order to rev-ivify the copper sub-oxide I may moisten the same with a v ry weak solution of zinc sulphate and r0 t in air at a temperature of 100 C. After treatmentin this way the copper sub-oxide becomes re-' activated and the operation of 'revivifying the vitiated copper sub-oxide can be repeated sub-oxide produced as aforesaid retains its activity fora prolonged period.

further feature of the pres- According to a formic acid is admitted in vapourform into the interior'of a distillation or a gas containing methane chamber, retort.or the like containing carbonaceous materials which-are undergoing distillation, the formlc acid being preferably produced as aforesaid from methane, air gas orcarbon monoxide by the aid of a suitable catalyst asa step in the process of distillatiofi. The carbonaceous material may contain a small per- Thehydrogen liberated during the reaction creased. In cases where -or, in the presence found that the converts or produces chemical changes in which results in the production of formic acid, being in the nascent state, is very active in promoting new hydrocarbon products, W111 e at the high temperature prevailing within the distillation chamber or retort, the formic acid is immediately decomposed and further nascent hydrogen is set free.

The catalytic reaction for the product1on of formic acid being endothermic, that 1s to say, requiring heat, the heat can conveniently be supplied by utilizing the socalled sensible or mechanical heat of the carbon monoxide of methane itself as it issues from anadjacent producer. After the reaction is completed or carried out to the desired extent, the spent gases, containing free formic'acid in the form. of vapour, may be injected or admitted to the distillation chamber, retort, or other chambercontaining the carbonaceous material or the hydroca'r-- bons which are being distilled .or converted. By employing free formic acid vapour in the manner above described, and utilizing the activity ofthe nascent hydrogen formed in the retort by the decomposition of the formic acid, the proportionate yield of liquid or condensible hydrocarbons is very greatly inthe distillation of carbonaceous materials is carried out in a retort which is heated internally by means of the sensible heat of producer gas, such as, for example, air gas as mentioned above or water gas,-it is possible to by-pass into a suitable chamber any convenient amount of such gas in the hot state at which it leaves the roducer, and, after the conversion of the w ole or part of the carbon monoxide into formic acid, this gas may be allowed to mingle, for the purpose ofgase's as they enter the retort, or it may be admitted at any other convenient point.

It is to be understood that the presentprocess may also be applied-to the conversion of liquid bons to this end being heated in a suitable chamber until they volatilize and the free formic acid being admitted to the said chamber, may lene gas may be converted into formic acid dehyde; The manufacture of acetic acid or the treatment or conversion of other hydrocarbons, industrial gases, -or' gases containing hydrocarbons, may also be effected by passin sub-oxide prepared as aforesaid, as I ave aforesaid copper subloxide the said gases.

What I claim and desire tosecure by Let:

ters Patent of the United States is of hydrogen into formal- 1 the same over an activated co per described, with the main supply hydrocarbons, the hydrocaror other gases of the hydrocarbon seri s be similarly treated, for example, acet 1. 'A metallic catalyzer for use in the I manufacture. of formic acid or the treatment or conversion ofhydrocarbon s consisting of all copper sub-oxide which has been precipiacid or 1n connection with the conversion or transformation of hydrocarbons which consists in precipitating copper from a solution of copper sulphate by means of metallic zinc, the copper sulphate being greatly in excess to ensure that no metallic 'zinc is present and the precipitate, (copper sub-oxide) after being boiled and Washed to remove all traces of zinc being afterwards dried and roasted.

3. A method of revivifying the copper sub-oxide catalyzer claimed in claim 1 which consists in moisten'ing the Vitiated or deoxidized copper sub-oxide with a weak solu-' tion of zinc sulphate.

4. A method of activating copper so as to render the same suitable for use as a catalyzer in the production offormic acid or in connection with the conversion or transfor-' mation of hydrocarbons which consists in moistening the copper with a weak solution of zinc sulphate and drying it in air.

HARALD NIELSEN 

